EDTA滴定法测定硅钙合金中钙含量的不确定度评定

THE UNCERTAINTY EVALUATION OF CALCIUM CONTENT IN SILICOCAI CIUM BY EDTA TITRATION

介绍了EDTA滴定法测定硅钙合金中钙含量的操作过程,分析了测定过程中不确定度的主要来源,对各不确定度分量进行了量化计算,得出合成标准不确定度、扩展不确定度及测定结果的置信区间.数据表明,EDTA滴定法测定硅钙合金中钙含量不确定度主要因素是EDTA标准滴定溶液的浓度、EDTA标准滴定溶液的用量、试液重复性测量以及量取试液的体积.当钙质量分数为31.20%时,其标准扩展不确定度为0.31%(k=2).

The paper introduces the operating process of EDTA titration method of measuring calcium content in silico-calcium,analyzes the main sources of uncertainty in the measuring process,calculates quantitatively the content of un-certainty,concludes the combined standard uncertainty,and expanded uncertainty and confidence interval of the measured results.The data shows that the main factors affecting the uncertainty of calcium content in silicocalcium de-termined by EDTA titration method are the concentration of EDTA standard titration solution,the amount of EDTA standard titration solution used,the measurement of test solution repeatability,and the volume of the measured test so-lution.When the calcium mass fraction is 31.20%,the standard expanded uncertainty is 0.31%(k=2).